Extended data:

1, trigonometric function is one of the basic elementary functions. It takes angle (the most commonly used radian system in mathematics, the same below) as the independent variable, and the angle corresponds to the coordinates of the intersection point between the terminal edge of any angle and the unit circle or its ratio as the dependent variable. Trigonometric function plays an important role in studying the properties of geometric shapes such as triangles and circles, and is also a basic mathematical tool for studying periodic phenomena.

2. Common trigonometric functions include sine function, cosine function and tangent function. The relationship between different trigonometric functions can be obtained by geometric intuition or calculation, which is called trigonometric identity.

3. Trigonometric functions are generally used to calculate the sides and angles of triangles with unknown lengths, and are widely used in navigation, engineering, navigation, surveying, engineering and other disciplines.

References:

Trigonometric Function _ Baidu Encyclopedia